Endothelium-dependent dilation (EDD) is impaired with aging, but there is significant variability among healthy middle-aged and older adults. We tested the hypothesis that EDD is related to white ...blood cell (WBC) count in healthy men and women aged 55 to 75 years (n=48) who have a WBC count within the clinically normal range. The peak forearm blood flow response to intrabrachial artery infusion of acetylcholine was inversely related to WBC count (r=-0.38; P=0.004) and was 34% smaller in subjects with higher versus lower WBC count (more versus less than the median of 5.0x10(9) cells per liter; P=0.001). Vascular smooth muscle responsiveness to NO (peak forearm blood flow response to sodium nitroprusside) was inversely related to WBC count (r=-0.30; P=0.02) but did not fully explain the associations with EDD. Inhibition of NO with N(G)-monomethyl-L-arginine reduced EDD in subjects with lower (-56%; P=0.01) but not higher WBC count. Tetrahydrobiopterin selectively improved EDD in subjects with higher WBC count (+35%; P=0.01) by increasing NO bioavailability. EDD was related (P<0.05) to neutrophil, eosinophil, and monocyte but not lymphocyte or basophil counts. Myeloperoxidase, which is secreted by neutrophils and monocytes, consumes NO and produces molecules that oxidize tetrahydrobiopterin, was inversely related to EDD (r=-0.35; P=0.02), and was 42% higher in subjects with a higher WBC count (P=0.02). No other factors contributed to the relation between EDD and WBC count. Among healthy middle-aged and older adults, impaired EDD is related to higher neutrophil, eosinophil, and monocyte-based WBC count mediated by reduced responsiveness to NO and increased myeloperoxidase-associated reductions in tetrahydrobiopterin and NO bioavailability.
Sensitivity Modeling for LiteBIRD Allys, E.; Arnold, K.; Auguste, D. ...
Journal of low temperature physics,
2023, Letnik:
211, Številka:
5-6
Journal Article
Recenzirano
Odprti dostop
LiteBIRD
is a future satellite mission designed to observe the polarization of the cosmic microwave background radiation in order to probe the inflationary universe.
LiteBIRD
is set to observe the ...sky using three telescopes with transition-edge sensor bolometers. In this work we estimated the LiteBIRD instrumental sensitivity using its current design. We estimated the detector noise due to the optical loadings using physical optics and ray-tracing simulations. The noise terms associated with thermal carrier and readout noise were modeled in the detector noise calculation. We calculated the observational sensitivities over fifteen bands designed for the LiteBIRD telescopes using assumed observation time efficiency.
The developing fetal skull base has previously been studied via dissection and low-resolution CT. Most of the central skull base develops from endochondral ossification through an intermediary ...chondrocranium. We traced the development of the normal fetal skull base by using plain radiography, MR imaging, and CT.
Twenty-nine formalin-fixed fetal specimens ranging from 9 to 24 weeks' gestational age were examined with mammographic plain radiography, CT, and MR imaging. Skull base development and ossification were assessed.
The postsphenoid cartilages enclose the pituitary and fuse to form the basisphenoid, from which the sella turcica and the posterior body of the sphenoid bone originate. The presphenoid cartilages will form the anterior body of the sphenoid bone. Portions of the presphenoid cartilage give rise to the mesethmoid cartilage, which forms the central portion of the anterior skull base. Ossification begins in the occipital bone (12 weeks) and progresses anteriorly. The postsphenoid (14 weeks) and then the presphenoid portion (17 weeks) of the sphenoid bone ossify. Ossification is seen laterally (16 weeks) in the orbitosphenoid, which contributes to the lesser wing of the sphenoid, and the alisphenoid (15 weeks), which forms the greater wing.
MR imaging can show early progressive ossification of the cartilaginous skull base and its relation to intracranial structures. The study of fetal developmental anatomy may lead to a better understanding of abnormalities of the skull base.
Objective. To develop an instrument for assessing physician attitudes toward quality incentive programs, and to assess its reliability and validity.
Data Sources. Study involved primary data ...collection. A 40‐item paper and pencil survey of primary care physicians in Rochester, New York, and Massachusetts was conducted between May 2004 and December 2004. Seven‐hundred and ninety‐eight completed questionnaires were received, representing a response rate of 32 percent (798/2,497).
Study Design. Based on an extensive review of the literature and discussions with experts in the field, we developed a conceptual framework representing the features of pay‐for‐performance (P4P) programs hypothesized to affect physician behavior in that context. A draft questionnaire was developed based on that conceptual model and pilot tested in three groups of physicians. The questionnaire was modified based on the physician feedback, and the revised version was distributed to 2,497 primary care physicians affiliated with two of the seven sites participating in Rewarding Results, a national evaluation of quality target and financial incentive programs.
Data Collection. Respondents were randomly divided into a derivation and a validation sample. Exploratory factor analysis was applied to the responses of the derivation sample. Those results were used to create scales in the validation sample, and these were then subjected to multitrait analysis (MTA). One scale representing physicians' perception of the impact of P4P on their clinical practice was regressed on the other scales as a test of construct validity.
Principal Findings. Seven constructs were identified and demonstrated substantial convergent and discriminant validity in the MTA: awareness and understanding, clinical relevance, cooperation, unintended consequences, control, financial salience, and impact. Internal consistency reliabilities (Cronbach's α coefficients) ranged from 0.50 to 0.80. A statistically significant 25 percent of the variation in perceived impact was accounted for by physician perceptions of the other six characteristics of P4P programs.
Conclusions. It is possible to identify and measure the key salient features of P4P programs using a valid and reliable 26‐item survey. This instrument may now be used in further studies to better understand the impact of P4P programs on physician behavior.
Abstract Introduction Tibial plateau fracture classification systems have limited interobserver reliability and new systems emerge. The purpose of this study was to compare the reliability of the Luo ...classification and the Schatzker classification for two-dimensional computed tomography (2DCT) and to study the effect of adding three-dimensional computed tomography (3DCT). Materials and Methods Eighty-one observers, orthopedic surgeons and residents, were randomized to either 2DCT or 2D- and 3DCT evaluation of a spectrum of 15 complex tibial plateau fractures using web-based platforms in order to classify according to the Schatzker and according to Luo's Three Column classification. Reliability was calculated with the use of Siegel and Castellan's multirater kappa measure. Kappa values were interpreted according to the categorical rating by Landis and Koch. Results Overall interobserver reliability of the Schatzker classification was significantly better compared to the Luo classification ( kSchatzker = 0.32 and kLuo = 0.28, P = 0.021), however, ‘fair’ for both fracture classification systems. For the Schatzker classification observers agreed significantly better on 2DCT compared to 2D- and 3DCT ( k2DCT = 0.37 and k2D+3DCT = 0.29, P < 0.001). The addition of 3DCT did not improve the overall interobserver reliability for the Luo classification as well, as kappa values were not significantly different on 2DCT and 2D- and 3DCT ( k2DCT = 0.31 and k2D+3DCT = 0.25, P = 0.096). Conclusions The agreement between observers was significantly better for the Schatzker classification compared to Luo's Three Column classification, however agreement was fair for both classification systems. Furthermore, the addition of 3DCT reconstructions did not improve the reliability of CT-based evaluation of tibial plateau fractures. Considering that new classification systems and 3DCT do not seem to improve agreement between surgeons, other efforts are needed that lead to more reliable diagnosis of complex tibial plateau fractures.
This article on digital radiography image processing and display is the second of two articles written as part of an intersociety effort to establish image quality standards for digital and computed ...radiography. The topic of the other paper is digital radiography image acquisition. The articles were developed collaboratively by the ACR, the American Association of Physicists in Medicine, and the Society for Imaging Informatics in Medicine. Increasingly, medical imaging and patient information are being managed using digital data during acquisition, transmission, storage, display, interpretation, and consultation. The management of data during each of these operations may have an impact on the quality of patient care. These articles describe what is known to improve image quality for digital and computed radiography and to make recommendations on optimal acquisition, processing, and display. The practice of digital radiography is a rapidly evolving technology that will require timely revision of any guidelines and standards.
An abstract by Kvidera et al on determining the effects of supplemental citrulline on intestinal neutrophil infiltration during heat stress (HS) and nutrient restriction in growing pigs is presented. ...In summary, HS and nutrient restriction increase neutrophil infiltration in the distal gastrointestinal tract. Supplemental citrulline does not diminish this immune response during HS but does ameliorate it under nutrient-restriction conditions.
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